N = int(input())
C = input()
T = 'R' * C.count('R') + 'W' * C.count('W')
ans = sum([1 for a, b in zip(C, T) if a != b]) // 2
print(ans) N = int(input()) N int(input()) int input() input C = input() C input() input T = 'R' * C.count('R') + 'W' * C.count('W') T 'R' * C.count('R') + 'W' * C.count('W') 'R' * C.count('R') 'R' C.count('R') C.count C count 'R' 'W' * C.count('W') 'W' C.count('W') C.count C count 'W' 1 for a, b in zip(C, T) if a != b for a, b in zip(C, T) if a != b a b zip(C, T) zip C T a != b a b if a != b 1 ans = sum([1 for a, b in zip(C, T) if a != b]) // 2 ans sum([1 for a, b in zip(C, T) if a != b]) // 2 sum([1 for a, b in zip(C, T) if a != b]) sum [1 for a, b in zip(C, T) if a != b] 2 print(ans) print ans C = input() input() C T = 'R' * C.count('R') + 'W' * C.count('W') 'R' * C.count('R') + 'W' * C.count('W') T N = int(input()) int(input()) N ans = sum([1 for a, b in zip(C, T) if a != b]) // 2 sum([1 for a, b in zip(C, T) if a != b]) // 2 ans
N = int(input())
C = input()
T = 'R' * C.count('R') + 'W' * C.count('W')
ans = sum([1 for a, b in zip(C, T) if a != b]) // 2
print(ans)